Advertisements
Advertisements
प्रश्न
In a ‘Mahila Bachat Gat’, Sharvari invested ₹ 2 on first day, ₹ 4 on second day and ₹ 6 on third day. If she saves like this, then what would be her total savings in the month of February 2010?
Advertisements
उत्तर
Amount invested by Sharvari in the month of February 2010 are as follows:
2, 4, 6,...
The above sequence is an A.P.
∴ a = 2, d = 4 – 2 = 2
Number of days in February 2010,
n = 28
Now, `S_n = n/2 [2a + (n - 1)d]`
∴ `S_28 = 28/2 [2(2) + (28 - 1)(2)]`
= 14[4 + 27(2)]
= 14(4 + 54)
= 14(58)
= 812
∴ Total savings of Sharvari in the month of February 2010 is ₹ 812.
APPEARS IN
संबंधित प्रश्न
Show that a1, a2,..., an... form an AP where an is defined as below:
an = 3 + 4n
Also, find the sum of the first 15 terms.
200 logs are stacked in the following manner: 20 logs in the bottom row, 19 in the next row, 18 in the row next to it and so on. In how many rows are the 200 logs placed, and how many logs are in the top row?
A ladder has rungs 25 cm apart. (See figure). The rungs decrease uniformly in length from 45 cm at the bottom to 25 cm at the top. If the top and bottom rungs are 2 `1/2` m apart, what is the length of the wood required for the rungs?
[Hint: number of rungs = `250/25+ 1`]
If the sum of first m terms of an A.P. is the same as the sum of its first n terms, show that the sum of its first (m + n) terms is zero
Which term of the progression 20, 19`1/4`,18`1/2`,17`3/4`, ... is the first negative term?
Find the sum of the following arithmetic progressions:
3, 9/2, 6, 15/2, ... to 25 terms
Find the sum of the first 25 terms of an A.P. whose nth term is given by an = 2 − 3n.
Find the sum of the first 22 terms of the A.P. : 8, 3, –2, ………
If the 8th term of an A.P. is 37 and the 15th term is 15 more than the 12th term, find the A.P. Also, find the sum of first 20 terms of A.P.
Find the sum of two middle most terms of the AP `-4/3, -1 (-2)/3, ..., 4 1/3.`
How many terms of the A.P. 21, 18, 15, ... must be added to get the sum 0?
If Sn denote the sum of n terms of an A.P. with first term a and common difference dsuch that \[\frac{Sx}{Skx}\] is independent of x, then
The sum of first n odd natural numbers is ______.
Q.18
Obtain the sum of the first 56 terms of an A.P. whose 18th and 39th terms are 52 and 148 respectively.
How many terms of the A.P. 25, 22, 19, … are needed to give the sum 116 ? Also find the last term.
How many terms of the A.P. 24, 21, 18, … must be taken so that the sum is 78? Explain the double answer.
The sum of first n terms of the series a, 3a, 5a, …….. is ______.
If the nth term of an AP is (2n + 1), then the sum of its first three terms is ______.
The sum of 40 terms of the A.P. 7 + 10 + 13 + 16 + .......... is ______.
